 Our galaxy does not want for alien horrors, those blights upon the purity of creation that insist upon sullying the grace of reality with their staining presences. Be they trogledetic crud or perfidious aildari or barbarian greenskin, their blasphemies know no end, but they are, in their own ways, products of the galaxy itself. However, difficult it may be to admit. Natural things, born of evolution, flourishing in their squattered niches, expanding outwards into humanity's duly deserved stars, the high fleets of the great devourer. However, they are from without. They are not galactic, no. Their origin lies far beyond the stars of this realm of ours. They are a thing from the outer darkness, the intergalactic void, born of creators or systems unknown. We know not how old they are nor from whence they came. There are some that speak of the species as a leviathan that is not just arriving in this galaxy from their own, but one that has devoured many, many galaxies upon their universal path, the ultimate existence scale predator. Just as a human body is a collection of cells bound together by the rigours of our own biology and form, so too is the tyrannid species one single gestalt organism, an unfathomably large sentience diffused throughout a race in its entirety. The hive mind, as we of the Imperium have come to term it, thinks and feels and plots and schemes and calculates. It is alive, and the individual organisms that blight humanity's worlds across the galaxy are simply aspects of this whole, cells within a galaxy spanning body. Hive is almost not quite the right term, its application serves only to best illustrate the swarming, multifarious hordes as akin to the insectoid species humanity has previously encountered. The tyrannids are less a hive and more a single body, reacting to stimuli and driven by a single consciousness, but a body for whom contiguous connectivity is rendered needless thanks to the gestalt psychic bond the species shares. It is this mind, however, that drives, sculpts, and guides the biology of its own body in a way that has terrified and haunted xenobiologists of the Imperium since we first made contact with this dread species. Know then that for the elucidation of those whom it may concern, that this is a record of that self-same biology, a discussion upon the blasphemous evolution and evolutionary capabilities of the tyrannid species. Autopsies upon this Xenos breed are, in some capacities far easier than examination of other Xenophorms, yet at the same time more challenging. Certainly we are rarely want for samples, one of the defining characteristics of the tyrannid species is their sheer, crushing, unimaginably large numbers, of which no estimate can apparently be applied. For everyone we have killed a thousand more have descended from the void to take the place of the fallen. Nevertheless, study is necessary, and herein shall lie the findings of select mechanicum biologist examinations. The tyrannid skeleton is not quite a skeleton in the way many other Xenos species throughout the galaxy ape the human perfect form, but rather a bonded endomuscular arrangement structured through exoskeletal resinous plates that, for the sake of ease, can be considered analogous to the chitin of many insectoid creatures found galaxy wide. That being said, this material is far sturdier, with numerous calcifying agents present that aid in not only its toughness but also its longevity. Chitin typically degrades at a far faster rate than this substance. Indeed, glands in the surrounding soft tissue indicate that it is extruded in a liquid form that hardens rapidly, allowing the creature to shed damaged or worn plating and replace it with stunning rapidity. What is incongruous, and must be noted for future discussion, is the presence of a skull analog of a dense calcified material disturbingly akin to human bone in the presence of many dissected tyrannid creatures across a range of separate species Xeniforms. In smaller creatures, such as the infamous tyrannospheriae, or gene stealer, this similarity is especially pronounced, which will again be elaborated upon later. It may in fact require its own record. The skull and its organs, however, are prime examples of the sheer diversity of form and function within the Xenos genus. The gene stealer's ocular organs, for instance, are similar to human eyes with a comparable visual range, albeit far greater clarity. Between the skull, however, of Tyrannus decimulus, the lictus, cavity space is given over from ocular organ complexity to bolster production of feeder tentacles, allowing the subject to not only consume a far greater degree of prey, but expand its sensory perception suite, as the tentacles contain a staggering array of scent and taste receptors of vast complexity. Between the side adjacent subspecies Tyrannus tyrannus, the archetypal tyrannid warrior form, such tentacles are given over to a mouth with carnivorous presenting teeth, but their ocular organs are instead formed of overlapping plates of photoreactive plasma, allowing for a sense of sight that is not only adaptive to wavelengths far beyond human basic, but even magnification. This gives but a simple example of the terrifying array of adaptations a tyrannid form is capable of expressing. While the senses discussed above are certainly interesting to the xenobiologist, it is of course the biological weaponry of the race that has been the primary focus of Ordo and Mechanicus research and inquiry. Depending upon the role the individual tyrannid organism is assigned by the hive mind, these weapon organs fulfill a variety of battlefield and combat requirements. For example, upon the lictor, claws of super dense variety of its skin chitin are developed with glands contained within them, secreting a chemical through fluid runnels that forms a coating of toxins on the sharpened edges of the claws. Lictors bear these as their primary offensive tools, but owing to their capacity as an infiltration or vanguard organism also possess a pair of manipulation hands as two of their six limbs. This is not the case with Tyrannus Tyrannus, who as befitting their role as frontline combat organisms share the hexapod form of the lictor as well as similar claw arms, but host parasitic weapon organisms in place of more subtle appendages. While these can normally be thought of as the creature's projectile weapon or gun, they are in fact as alive as the host warrior itself, if possessing no neural net or sentience of their own. Tyrannus Tyrannus are outfitted with whichever biomorph the hive mind deems necessary. Two of the most commonly observed, dubbed biocannons and devourers by the Imperium themselves contain yet more organisms, effectively making these creatures three organisms in one. In the case of biocannons, the creatures contained within are fired through a bioelectrical pulse at a target, only for their swollen forms to split upon impact, coating the target with a dense layer of monomolecular acid that rapidly corrode all material it touches. The devourer functions similarly, although the organisms it fires are akin to maggot worms with burrowing mouths, intended to eat through the flesh of organics and target nervous systems and brain stems, resulting in painful but quick departures from the mortal plane. As is no doubt obvious to talented acolytes, we see here two weapon expressions designed, and I use the word deliberately, for two entirely different combat scenarios. One where armor or indeed armored vehicles are an issue, and one where organic foes are present in large numbers. Further sub-expressions of these weapons have been routinely encountered by Imperial forces, such as devourers whose ammunition has developed stronger and more resilient mandibles to chew through heavier flak or carapace armor with terrifying rapidity. Analysis of the DNA of the Tyranid species is, as with the autopsies of creatures themselves, filled with results more variable than science would seem to allow. No two organisms possess identical genetic strands, of course, and this is to be expected within species with such pronounced sub-mutations. Even humanity possesses such examples, Homo Navigo, Homo sapiens gigantes, Homo sapiens rotundus, or navigators, augurans, and squats, depending on their crudely unscientific nomenclature. However, within Tyranids, DNA samples may vary within the creatures themselves, either within samples taken from different organs, or even from adjacent chitin plates or muscular structures. The chemical bond helix common in species of this galaxy, albeit varying complexity, is completely absent. It has been replaced by an array of combined and apparently foreign DNA analog bonds fused together by means utterly unknowable. Even reading of it, one cannot help but shudder that blasphemy. These creatures are not just a colony of composite organisms, they are constructs of stolen DNA, gene-coding apparently torn and bio-alchemically arranged from innumerable other creatures. This code is a product of craftsmanship in, and I apologize for this blatantly heretical analogy, anastartesis. Based on something natural, yes, but yet so wholly and utterly crafted as to have shucked the bonds of simple, environmentally driven evolution. This is one reason why xenobiological study and classification of Tyranid geno strains has proven highly difficult for both the Mechanic and Biologis and the Ordosinos. Quite beyond their DNA, what shared physical traits the majority of organisms express are limited essentially to their root endo and exoskeletal structures, namely the chitinous plates and bonded muscle analog masses. Beyond that, each differs so wildly in form, function, and expression that were they not verified upon thousands of occasions as belonging to the same species, they would demand reclassification as separate genus types by any sane standards of taxonomy. And this, even, is only when discussing the Xeno in broad strokes. As mentioned with the case of Devourer organism ammunitions, localized hyper-adaptation has been recorded in hundreds of instances where the Imperium has been engaged in protracted conflicts with the species. Should a certain type of organism meet the continued battlefield failure, the hive mind will simply retire that pattern and develop in absolutely horrific rapidity a similar strain with adaptations designed to overcome the issue that had stymied its predecessor. Mechanicus Genitor Field Expeditionary Team, operating out of the Avarni sector on a five-year study, was able to initially render a report that, in broad terms, summarized the paradigm of Tyranid generational evolution as the Imperium can best understand it. For the purposes of this analysis, the genitor primus dubbed the root organisms commonly encountered by Imperial armed forces, for our own example, let us state Tyranus Tyranus, the Tyranid warrior, as A, the study group, as well as representing the qualities inherent of the organism per Imperial standard, its physical features, its physical capabilities, and its parasite weaponry. Beyond this, X and Y will serve to represent foreign qualities absorbed by the hive mind during a particular combat scenario that A organism is involved in, structural, chemical, neurological, physical, biological, any and all potentially occurring factors. To demonstrate this, the study will frame each generation in the form of a successful combat scenario, such as a planetary invasion or void boarding engagement, namely a scenario where the hive in question is provided with ample quantities of X and Y, as well as the raw materials necessary to facilitate generational reproduction. During typically the first one to three generations, the hive possesses a population of A organisms based on a standard template, namely the one that has been known to provide versatility of usage as well as effectiveness that has been proven countless other times. We know this to be the case as morphologically identical Tyranid creatures have been encountered in entirely different galactic regions belonging to completely different hive fleets. The hive mind, in short, knows what works and remembers. During these initial generations, the hive nevertheless experiments with successor batches of A organisms, producing, for the purpose of this study, AX and AY strains. Again, for the purpose of argument, let us say that AX underperforms to the hive's expectations. The hive is aware of this, and the cost benefit of producing more broods of AX is considered a net loss for the hive's intake of biomass. Thus, AX is retired, in that future generations are either immediately ceased or appear far less frequently, while AY is seen in greater numbers, serving alongside the base A organisms. Should AY perform exceedingly well, it may even usurp A as the dominant root organism of that particular geniform that the hive is employing. Fascinatingly, in the case of this genitor expedition, AX was in fact encountered at a later date, when imperial forces had shifted their tactics to account for the higher than average encounter rate with AY. This suggests that the hive fleets possess a form of localized and specific genetic archiving, allowing them to save genetic templates for later use through the situation arise, preventing them from having their own hyper evolution serve as a vulnerability, backing them into a corner, so to speak. Perhaps most frighteningly, and only verifiable through macro analysis of localized studies such as this, is the appearance of evolutionary synchronicity across massive stellar volumes, and between nominally unrelated hive fleets, or, to couch it in this study's terms, the appearance of quality Y in completely dissimilar organism B. That this evolution is directed, is verifiable by any standards of study, but breaking it down into its component formula yet retains the ability to sicken. While the hive mind itself is the ultimate driver behind any of this evolutionary adaptation, in local terms, imperial xenobiologists have nominally confirmed the existence of what have been dubbed Norn Queens, essentially an almost starship-sized organism that serves as a reproductive locus of an individual hive. Initially, these organisms were only thought of as brood vessels responsible for discorging organisms into imperial planets, with genitors, magi, and inquisitors arguing endlessly over whether or not the spawning ships had any degree of input into the hive's actions or courses. Thanks to numerous boarding actions by the Adeptus Astartes, it has been confirmed, as many magi once hypothesized, that Norn Queens do in fact exist as distinct organisms, and that they do so with a far greater degree of intelligence, and perhaps even autonomy than the majority of tyrannites possess. The degree to which we could term them separate sentient creatures is still widely and hotly debated, with only the Swarm Lord serving as an example of how this could even function within such a species. However, as evolutionary loci, the Norn Queens are believed to be responsible for the sum of the intake, processing, and distribution of both the biomass a hive fleet consumes, and the associated genetic material. Everything the hive touches the Norn Queen knows, and everything the hive fleet needs the Norn Queen can provide. They are genetic archive, as discussed earlier. Or rather, they serve as one through their connection to the hive mind, weaving out of the psychic gestalt the information required to produce the base organism strains, and in loading and calculating the qualities they may introduce to iterative generational gene coding. Spiders, in the center of an impossibly large web, weavers of the unimaginably blasphemous, they are utterly alien things of darkest nightmare. By one Astartes report, they are a heaving gargantuan mass of biology, spawning broods of creatures fully formed and matured, churning out gelatinous egg sacks from their bulk in the thousands, casings that hothouse the organisms within to combat or logistic readiness in comparatively the blink of an eye. The conclusion to any study of the tyrannid species belies only one answer. There is simply no finer expression of macro evolutionary forces than they. The species has claimed its own evolution, wielding it as we would knife a weapon. We cyberize ourselves with crude mechanics. We pluck at our genetics. They are one. They are whole. They do it themselves. The species is truly an apex predator, a fiendish intelligence of wicked capabilities capable of sculpting its own form to simply overcome the problems around it. Only through desperate means has the Imperium, or even other Xenos races, been able to overcome the high fleets of the tyrannids. I shall, as I have access to the recording, place the burden of capstoning this particular examination of the species upon the man who essentially discovered them. Inquisitor Cryptman. Until such a time, as we may discuss further, the Imperator. Gloria, Greek Celsus, Terra. built only to kill. And when the mouth closes, it shall not be to honor the Supreme Emperor, or soothe our peace, or discuss terms. It shall be to swallow our Imperium whole. We call them tyrannids as if they're a race. Another Xenos clan to be face down and cleansed. In the face of horror, we cling to our sciences, our labels, little realizing they do nothing but drowmas. We do better to call them a disease. There is no better analogy. I've seen the high ships, brothers. Barbed horrors scuttling forth to kill. Bloated vermin riving back to be absorbed. Their bellies fall. I've seen the forest pick clean of life. I've seen the biofleets draining the water of teeming worlds. The vortex mouths gozzling the prairies. I've seen the shadows moving in the warp. The tentacles stretching out of the darkness beyond the eastern rim. This is the end of times, brothers. Death approaches, and it is not at the hands of a ravening horde, nor an army of contemptible aliens. Our enemy is a single intellect. A single gestalt consciousness. More ancient than we can conceive. More massive than we can measure. A single mind that has not one body, but a trillion. An all-seeing eye that has no shape and no form. How can we fight such a thing? I will tell you. Until our last breath. If we come but delayed the great moth from closing around us, then we have achieved what countless empires, countless worlds, countless galaxies, have not. I say this not to terrify you. I say it simply so you understand. Simply so you do not waste your time with such luxuries as hope. There is no hope. The greater devour is upon us. Let us see how long we may restrain her jaw. Inquisitor Kripman addressing the congresium zenos 992-M41 Otherwise, please like, subscribe, comment, let me know your feedback, and as ever, thank you very much for watching.